A Fluorescence Detector Based On Metallic-wave Guide-capillary

Rhodamine b,commonly known as pink flowers,also called red rose B,or rhodamine,is a very bright red dye synthetic.Some vendors often use it in foods as tonyred substitutes,which has strong carcinogenicity.Therefore,it has important research value for the detection of trace rhodamine b.Now,there are few great ways of rhodamine detection,the ways are not only high cost,but also have low detection limit.Fluorescence refers to the phenomenon that a substance absorbs light of a certain wavelength and emits light of another wavelength.Rhodamine b is a common fluorescent substance.This paper have researched the current rhodamine b detection methods and detection limit and compared the advantages and disadvantages of various detection methods.On this basis,this paper puts forward a kind of trace rhodamine b detection method based on metal wave guide capillary,using the fluorescence characteristics of rhodamine b.We use the green light source of 520 nm as the exciting light and collect the fluorescence at the length of more than 600 nm to test the water solution.The special metal waveguide capillary sensor increases the reflection times of the light on the inner wall of the capillary tube,and greatly improves the optical path,thus improving the limit of the test.In the process of testing,the effect of different excitation intensity on the test limit was studied and the intensity of the stimulated light was changed by changing the voltage of the laser diode.It is found that the intensity of fluorescence is closely related to the intensity of the excitation light.Therefore,it is very important to select the appropriate voltage to improve the test limit.In order to prove the advantages of the metal waveguide capillary,we also use the current mainstream products in the market--the fluorescence spectrophotometer to make a comparative test.The results show that the peak limit of the metal waveguide capillary is much higher than that of the spectrophotometer,up to 10^-13g/ml.Compared with the spectrophotometer,the size and cost of the metal waveguide capillary sensor are greatly reduced,after the day is expected to replace the spectrophotometer as optical detection of trace substances of choice.